000
AXPZ20 KNHC 020255
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU MAY 02 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS W FROM THE BORDER OF COLOMBIA
AND PANAMA ACROSS CENTRAL PANAMA TO THE PACIFIC AT 11N92W 
THEN SW TO 10N97W WHERE SCATTEROMETER WINDS INDICATE
A TRANSITION TO AN ITCZ. THE ITCZ AXIS CONTINUES SOUTHWESTERLY
TO 05N130W THEN NW TO BEYOND 08N140W. SCATTERED MODERATE
ISOLATED STRONG CONVECTION IS OBSERVED S OF THE EASTERN 
SEGMENT OF THE MONSOON TROUGH AXIS ROUGHLY WITHIN 90
NM EITHER SIDE OF A LINE FROM 08N86W TO 07N100W...WITH 
THE CONVECTION CURRENTLY DECREASING IN BOTH COVERAGE AND 
INTENSITY. ISOLATED CLUSTERS OF MODERATE CONVECTION IS
NOTED OVER AND JUST TO THE S OF THE ITCZ AXIS BETWEEN 
120W AND 136W. 

LOCALLY OVERCAST MULTI-LAYERED CLOUDS...WITH SCATTERED
MODERATE CONVECTION OCCASIONALLY FLARING WITHIN THIS CLOUD
MASS...IS ENHANCED ALONG THE W PERIPHERY OF AN UPPER 
RIDGE IN THE AREA JUST N OF THE ITCZ ROUGHLY WITHIN 120 NM
EITHER SIDE OF A LINE FROM 10N127W TO 19N118W. THE 
RESULTANT UPPER DEBRIS MOISTURE CONCENTRATES INTO A 300
NM WIDE MOISTURE PLUME THAT STREAMS E ACROSS MEXICO FROM 18N
TO 24N AND EVENTUALLY FEEDS INTO A CLUSTER OF CONVECTION 
ADVANCING SE OVER THE S-CENTRAL GULF OF MEXICO.
  
...DISCUSSION... 
GULF OF CALIFORNIA...S TO SW WINDS HAVE BEEN AT 5 TO 10 KT
ACROSS THE ENTIRE THE GULF OF CALIFORNIA WITH SEAS OF 1 TO
2 FT...EXCEPT 2 TO 4 FT OVER THE SOUTHERN GULF OF CALIFORNIA
WATERS PRIMARILY DUE TO LONG PERIOD CROSS EQUATORIAL SOUTHERLY 
SWELL. THIS LIGHT SOUTHERLY FLOW WILL BECOME NORTHERLY BY
MIDNIGHT TONIGHT...THEN INCREASE 20 TO 25 KT OVER THE WATERS 
N OF 30N...WHILE MOSTLY 10 TO 15 KT ACROSS THE WATERS S OF 
30N BY SUNRISE THU. THESE STRONG NW WINDS WILL QUICKLY SPREAD
S ACROSS ALL THE GULF WATERS N OF 26N ON THU AFTERNOON WITH
SEAS BUILDING 5 TO 8 FT IN THE LONG NW TO SE FETCH NEAR 30N.
THE GRADIENT WILL RELAX ON THU NIGHT INTO FRI WITH THE N
FLOW DIMINISHING TO LIGHT AND VARIABLE WINDS...AND SEAS 
SUBSIDING TO 2 FT OR LESS ON FRI NIGHT. THE LOW LEVEL FLOW 
WILL BECOME SOUTHERLY AGAIN ON SAT INCREASING TO 10 TO 15
KT. A SURFACE LOW PRESSURE CENTER IS EXPECTED OVER THE FAR
NORTHERN WATERS ON SUN NIGHT...AND ACCOMPANIED BY CYCLONIC
15 TO 20 KT WINDS.

GULF OF TEHUANTEPEC...S TO SW WINDS AT 5 TO 10 KT ARE
EXPECTED ACROSS THE GULF OF TEHUANTEPEC THROUGH THU EVENING.
NORTHERLY WINDS WILL SURGE THROUGH THE CHEVILA PASS LATE
THU NIGHT...INITIALLY AT 10 TO 15 KT...BUT QUICKLY INCREASE
20 TO 30 KT BY LATE FRI AFTERNOON AS SEAS BUILD TO 10 FT.
THE N FLOW WILL INCREASE TO MINIMAL GALE FORCE FRI NIGHT 
AND CONTINUE THROUGH MAXIMUM DRAINAGE JUST AFTER SUNRISE
ON SAT...WITH SEAS BUILDING TO 13 FT NEAR 14.5N95W AT
SUNRISE SAT. THE WINDS WILL DIMINISH LATE SAT MORNING WITH
SEAS OF 8 FT REACHING AS FAR S AS 10N96W ON SAT EVENING.
THE NE SWELL WILL PROPAGATES SW AND GRADUALLY SUBSIDE TO
6 FT ON SUN AND 5 FT SUN NIGHT. WINDS WILL BECOME LIGHT 
AND VARIABLE ACROSS THE GULF OF TEHUANTEPEC ON SUN WITH
LITTLE CHANGE THROUGH MON. 

GULF OF PAPAGAYO...LIGHT AND VARIABLE WINDS AND LONG PERIOD
SW SWELL...WITH SEAS 3 TO 5 FT...ARE EXPECTED THROUGH SAT
EVENING...THEN E-NE FLOW AT 10 TO 15 KT IS FORECAST BRIEFLY 
FROM LATE SAT NIGHT INTO SUN MORNING AND AGAIN ON SUN NIGHT
INTO MON MORNING. 

GULF OF PANAMA...LIGHT AND VARIABLE WINDS AT 5 TO 10 KT ARE
EXPECTED THROUGH SUN.

SURFACE HIGH PRESSURE IS ANALYZED NW OF THE AREA WITH A RIDGE 
AXIS EXTENDING SE INTO THE DISCUSSION AREA FROM 32N137W TO 
18N110W. THE GRADIENT IS SUPPORTING N WINDS AT 15 TO 20 KT
ACROSS THE PACIFIC WATERS N OF 27N BETWEEN 120W AND 134W WITH 
SEAS 7 TO 11 FT PRIMARILY DUE TO N SWELL. THE AFFECTED AREA
WILL GRADUALLY SHRINK ON THU WITH WINDS LESS THAN 20 KT AND
SEAS LESS THAN 8 FT BY THU EVENING. THE RIDGE WILL SHIFT S
LATE IN THE WEEK ALLOWING A WEAK COLD FRONT TO SWEEP E ACROSS
THE PACIFIC WATERS N OF 27N E OF 115W ON FRI AND SAT...BUT
ONLY ACCOMPANIED BY 5 TO 10 KT SW TO W TO NW WIND SHIFT.   
 
$$
NELSON